As Mayweather explains, "there are stars, superstars, and supermegastars. Tom Cruise is a superstar. But I make stars starstruck. I'm a supermegastar."

Mayweather would repeat this speech—questioning Cruise's acting chops and Hilton's chops for doing, well, anything—at least three times during his interview and photo shoot for Men's Health. He's determined to flaunt his greatness, and trust me, it's not easy to look away.

Call It What You WantAcross Mayweather's T-shirt are the words "philthy rich," just in case, I suppose, the diamond boxing gloves draped around his neck, or the cash wedge he pulls from his pocket, or the Mayweather emblem in place of the Maybach logo on his Benz aren't proof enough.

For 2 hours, he's insisted how rich, famous, and talented he is, but I've come to realize the only things faster than Mayweather's mouth are his feet.

Mayweather, a 150-pound, baby-faced, self-proclaimed "greatest athlete ever," moves panther-fast as he swings his fists while taking verbal shots at musicians Pharrell Williams and Kanye West. At 30, he exhibits the antics of an arrogant, 15-year-old rich kid who needs the piss beat out of him.

Trouble is, no one can do it.

Mayweather is a five-time world-champion boxer in four weight classes, with an undefeated (37-0) record. On May 5, he squares off against Oscar De La Hoya for the junior middleweight championship, which will be the fifth weight class Mayweather has fought in.

Ten weeks prior to the fight, Mayweather has yet to officially begin his physical training, but you can bet his head is already in the game. His confidence, or cockiness—"call it what you want, but you can call me a winner," he says—is key to his success.

An athlete and an entertainer, Mayweather trains for performance and attention. But he has another objective that's even more ambitious: to motivate and inspire friends and family who watch him work out. And it's more important now that he do this than it's ever been.

Family MattersOver the past few years, Mayweather's family has struggled with type-2 diabetes—it's struck his Uncle Roger, grandmother, and father. Lately, his mother has been ill, and as a result, her weight has ballooned, which puts her at high risk of the disease, too.

Mayweather desperately wants his mom to lose pounds. But he also wants the rest of the world to know what makes you healthy and what doesn't work. "How come you never see anyone go on TV and say, 'I didn't work hard, and I didn't get in shape'?" he asks. Sick of diet and fitness gimmicks, he has a business project in the works called Mayweather Fitness. He envisions it as a hybrid of an old-school boxing gym and a commercial health club, designed to help members kick up the intensity of their workouts to Mayweather level.

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